fix: /https/settings shows the https section and switches https.acme_staging, for the Router Manager.

ADR.md

@@ -537,7 +537,9 @@ unchanged. Both services always listen on `127.0.0.1` as well as on the interfac
 never takes from the client. Let's Encrypt issues at most 5 certificates a week for the same
 names, which routers rebuilt for tests reach; `https.acme_staging` sets Caddy's global `acme_ca`
 to Let's Encrypt's staging directory, which replaces Caddy's default CAs for every site, so no
-test certificate comes from a production CA.
+test certificate comes from a production CA. `PUT /https/settings` changes `acme_staging` alone:
+the other settings of the section switch HTTPS off or move its ports, which would end the
+connection the Router Manager makes the change on.
 
 Consequences: HTTPS needs `wan.local_fqdn` in public DNS pointing at the router and port 80
 reachable from the internet; until then Caddy retries and the HTTPS ports do not answer. The